DE-AS 1090381 describes a method of coating dosage forms with coating materials that are soluble in the stomach. These contain a copolymer of 20-80% of at least one amino ester of (meth)acrylic acid and 80-20% of a monomer that forms a water-insoluble polymerizate as homopolymer. The esters of acrylic acid and (meth)acrylic acid with N,N-dimethylaminoethanol, N,N-diethylaminoethanol, N,N-dimethylaminopropanol and N-(hydroxyethyl)morpholine are mentioned as concrete examples of suitable polymerizable amino esters. Lower esters of acrylic acid and preferably of (meth)acrylic acid, such as ethyl acrylate, methyl, butyl and hexyl (meth)acrylate are mentioned as suitable comonomers. They are produced by solution polymerization in an organic solvent; no example is given.
DE-AS 1219175 describes a method of production of preparations of active compounds for use in veterinary medicine, which are protected against the action of ruminal fluid of ruminants. For this purpose, these preparations are coated with copolymers containing N,N-dialkylaminoalkyl(meth)acrylamides and a comonomer, incorporated by polymerization, which is selected from (meth)acrylates, acrylonitrile and vinylic aromatics. Copolymers based on N,N-dialkylaminoalkyl(meth)acrylates are, according to the teaching of this document, regarded as disadvantageous, as the ester group, compared with the amide group, is saponified earlier in the basic environment.
DE-OS 2135073 describes coating materials for dosage forms that contain an aqueous polymer dispersion, with the polymer consisting to 10-55 wt. % of monomers with a carboxyl group and/or a monoalkyl- or dialkylaminoalkyl ester group. Diethylaminoethyl methacrylate (DEAEMA) is mentioned as a suitable monomer, in addition to many others. The lower esters of (meth)acrylic acid, preferably methyl methacrylate, (meth)acrylonitrile, vinylic aromatics, vinyl chloride and vinyl acetate, are mentioned as suitable comonomers. Production takes place by aqueous emulsion polymerization, preferably according to the fed-batch emulsion process. Actual emulsion polymerizates based on DEAEMA are not disclosed.
DE-AS 2512238 teaches, for the preparation of binders for pharmaceutical coatings with low residual monomer content, the use of a powder obtained by spray-drying of a polymer dispersion for the production of coating solutions for these dosage forms. Regarding the dispersions used for spray-drying, reference is made to DE 1090381, DE 1219175 and DE 2135073.
DE-OS 2838278 describes coatings for oral dosage forms for ruminants from a) at least one film-forming polymer with at least one basic amino group and with a nitrogen content of 3-14%, which is soluble within 24 hours in aqueous ruminal medium at a pH of more than 5.5, and b) at least one hydrophobic substance dispersed in the polymer, selected from C12-C32 fatty acids, aluminum salts of these fatty acids and/or polycarboxylic acids.
A solution in an organic solvent is used for production of the coating. A large number of nitrogen-containing homo- and copolymers are listed as suitable polymers, without going into suitable methods for their production. A copolymer of 40% N,N-diethylaminoethyl methacrylate is given as example 29, though without stating a method of production thereof.
GB 1324087 describes coating polymers for oral dosage forms for ruminants, which contain a) at least one N,N-dialkylaminoalkyl(meth)acrylate and b) at least one ethylenically unsaturated compound, which is selected from vinylic aromatics and derivatives thereof, vinyl esters, esters of (meth)acrylic acid and acrylonitrile, incorporated by polymerization. N,N-dimethylaminoethyl methacrylate (DMAEMA) and tert-butylaminoethyl methacrylate (TBAEMA) are disclosed as suitable monomers a). In particular, methyl methacrylate is regarded as unsuitable as comonomer b), as it tends to form fragile coatings. Bulk, suspension, solution and emulsion polymerization are stated as suitable methods of polymerization. The copolymers in the examples were produced by solution polymerization.
DE 3426587 A1 describes a method of coating dosage forms by applying a film of a liquid, film-forming coating material, which contains a dissolved polymerizate with tertiary ammonium salt side groups. For production of these polymer solutions, among other means, copolymers based on N,N-dialkylaminoalkyl(meth)acrylates can be transformed with aqueous inorganic or organic acids to aqueous solutions of ammonium salts.
DE 3049179 A1 is an additional application to DE 2512238 and relates to the use of a powder, obtained by spray-drying according to the teaching of the latter document, in the form of an aqueous suspension, which additionally contains a plasticizer, for the production of coatings by thermal gelation.
EP 0058765 A2 describes coating materials for dosage forms soluble or swellable in gastric juice, and contain, as binder, an emulsion polymerizate based on N,N-dialkylaminoalkyl(meth)acrylates, with a branched alkylene or aralkylene group, with at least three carbon atoms arranged in a straight chain, being located between the amino group and the (meth)acrylate group.
WO 2005/055986 and WO 2005/056619 describe polymers with pH-dependent swelling/dissolution behavior and use thereof in dosage forms.
WO 00/05307 relates to the preparation of coating materials and binders for dosage forms, which contain (meth)acrylate copolymers, having monomer residues with tertiary amino groups, and simple dry or aqueous further processing is said to be possible. For this, this document teaches a method in which (a) a copolymer of C1-C4 esters of (meth)acrylic acid and (meth)acrylate monomers, which have tertiary ammonium groups, (b) a plasticizer and (c) an emulsifier with an HLB value of at least 14, are mixed together and the coating material or binder is produced therefrom by melting, pouring, spreading or spraying, copolymer (a) being applied in the form of powder with an average particle size of 1-40 μm. The resultant processability is attributed to the provision of copolymer (a) in powder form with extremely small grain size.
WO 02/067906 relates to coatings and binders with improved permeability to water vapor relative to those described in WO 00/05307. The coatings and binders are produced with a mixture containing (a) a copolymer of C1-C4 esters of (meth)acrylic acid and other (meth)acrylate monomers with functional tertiary ammonium groups in powder form with an average particle size of 1-40 μm, (b) an emulsifier with an HLB value of at least 14 and (c) a C12-C18 monocarboxylic acid or a C12-C18 hydroxyl compound.
WO 2004/019918 describes coatings and binders that correspond, with respect to their composition, to those described in WO 00/05307 and WO 02/067906.
According to U.S. Pat. No. 6,696,085 B2, a methacrylic acid copolymer of type C is used as a disintegrant. The methacrylic acid copolymer of type C is an enteric polymer, which is insoluble at acid pH, but is water-soluble at pH of about 7, as in the oral cavity. In addition to a low breaking strength (<20N), the tablets have high friability (>7%) and have a high proportion of a coarse-grained disintegrant, in the region of 15 wt. %. Consequently they have low mechanical strength and produce an unpleasant, sandy sensation in the mouth, owing to the high proportion of coarse-grained disintegrant.
The matrix components based on sugar alcohols, disintegrants and insoluble polymers are generally known for pharmaceutical applications from WO 2007/071581.
The production of the aqueous polymer dispersions of cationic polymers based on N,N-diethylaminoethyl methacrylate, as used according to the invention and their use for the coating of pharmaceuticals, is known from WO 2009/016258. However, the coating materials described in this document still leave something to be desired in stress storage with respect to stability of release and resistance to discoloration.